1 /* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
2
3 /*
4 * Internal libbpf helpers.
5 *
6 * Copyright (c) 2019 Facebook
7 */
8
9 #ifndef __LIBBPF_LIBBPF_INTERNAL_H
10 #define __LIBBPF_LIBBPF_INTERNAL_H
11
12 #include <stdlib.h>
13 #include <byteswap.h>
14 #include <limits.h>
15 #include <errno.h>
16 #include <linux/err.h>
17 #include <fcntl.h>
18 #include <unistd.h>
19 #include <sys/syscall.h>
20 #include <libelf.h>
21 #include "relo_core.h"
22
23 /* Android's libc doesn't support AT_EACCESS in faccessat() implementation
24 * ([0]), and just returns -EINVAL even if file exists and is accessible.
25 * See [1] for issues caused by this.
26 *
27 * So just redefine it to 0 on Android.
28 *
29 * [0] https://android.googlesource.com/platform/bionic/+/refs/heads/android13-release/libc/bionic/faccessat.cpp#50
30 * [1] https://github.com/libbpf/libbpf-bootstrap/issues/250#issuecomment-1911324250
31 */
32 #ifdef __ANDROID__
33 #undef AT_EACCESS
34 #define AT_EACCESS 0
35 #endif
36
37 /* make sure libbpf doesn't use kernel-only integer typedefs */
38 #pragma GCC poison u8 u16 u32 u64 s8 s16 s32 s64
39
40 /* prevent accidental re-addition of reallocarray() */
41 #pragma GCC poison reallocarray
42
43 #include "libbpf.h"
44 #include "btf.h"
45
46 #ifndef EM_BPF
47 #define EM_BPF 247
48 #endif
49
50 #ifndef R_BPF_64_64
51 #define R_BPF_64_64 1
52 #endif
53 #ifndef R_BPF_64_ABS64
54 #define R_BPF_64_ABS64 2
55 #endif
56 #ifndef R_BPF_64_ABS32
57 #define R_BPF_64_ABS32 3
58 #endif
59 #ifndef R_BPF_64_32
60 #define R_BPF_64_32 10
61 #endif
62
63 #ifndef SHT_LLVM_ADDRSIG
64 #define SHT_LLVM_ADDRSIG 0x6FFF4C03
65 #endif
66
67 /* if libelf is old and doesn't support mmap(), fall back to read() */
68 #ifndef ELF_C_READ_MMAP
69 #define ELF_C_READ_MMAP ELF_C_READ
70 #endif
71
72 /* Older libelf all end up in this expression, for both 32 and 64 bit */
73 #ifndef ELF64_ST_VISIBILITY
74 #define ELF64_ST_VISIBILITY(o) ((o) & 0x03)
75 #endif
76
77 #define JUMPTABLES_SEC ".jumptables"
78
79 #define BTF_INFO_ENC(kind, kind_flag, vlen) \
80 ((!!(kind_flag) << 31) | ((kind) << 24) | ((vlen) & BTF_MAX_VLEN))
81 #define BTF_TYPE_ENC(name, info, size_or_type) (name), (info), (size_or_type)
82 #define BTF_INT_ENC(encoding, bits_offset, nr_bits) \
83 ((encoding) << 24 | (bits_offset) << 16 | (nr_bits))
84 #define BTF_TYPE_INT_ENC(name, encoding, bits_offset, bits, sz) \
85 BTF_TYPE_ENC(name, BTF_INFO_ENC(BTF_KIND_INT, 0, 0), sz), \
86 BTF_INT_ENC(encoding, bits_offset, bits)
87 #define BTF_MEMBER_ENC(name, type, bits_offset) (name), (type), (bits_offset)
88 #define BTF_PARAM_ENC(name, type) (name), (type)
89 #define BTF_VAR_SECINFO_ENC(type, offset, size) (type), (offset), (size)
90 #define BTF_TYPE_FLOAT_ENC(name, sz) \
91 BTF_TYPE_ENC(name, BTF_INFO_ENC(BTF_KIND_FLOAT, 0, 0), sz)
92 #define BTF_TYPE_DECL_TAG_ENC(value, type, component_idx) \
93 BTF_TYPE_ENC(value, BTF_INFO_ENC(BTF_KIND_DECL_TAG, 0, 0), type), (component_idx)
94 #define BTF_TYPE_TYPE_TAG_ENC(value, type) \
95 BTF_TYPE_ENC(value, BTF_INFO_ENC(BTF_KIND_TYPE_TAG, 0, 0), type)
96
97 #ifndef likely
98 #define likely(x) __builtin_expect(!!(x), 1)
99 #endif
100 #ifndef unlikely
101 #define unlikely(x) __builtin_expect(!!(x), 0)
102 #endif
103 #ifndef min
104 # define min(x, y) ((x) < (y) ? (x) : (y))
105 #endif
106 #ifndef max
107 # define max(x, y) ((x) < (y) ? (y) : (x))
108 #endif
109 #ifndef offsetofend
110 # define offsetofend(TYPE, FIELD) \
111 (offsetof(TYPE, FIELD) + sizeof(((TYPE *)0)->FIELD))
112 #endif
113 #ifndef __alias
114 #define __alias(symbol) __attribute__((alias(#symbol)))
115 #endif
116
117 /* Check whether a string `str` has prefix `pfx`, regardless if `pfx` is
118 * a string literal known at compilation time or char * pointer known only at
119 * runtime.
120 */
121 #define str_has_pfx(str, pfx) \
122 (strncmp(str, pfx, __builtin_constant_p(pfx) ? sizeof(pfx) - 1 : strlen(pfx)) == 0)
123
124 /* suffix check */
str_has_sfx(const char * str,const char * sfx)125 static inline bool str_has_sfx(const char *str, const char *sfx)
126 {
127 size_t str_len = strlen(str);
128 size_t sfx_len = strlen(sfx);
129
130 if (sfx_len > str_len)
131 return false;
132 return strcmp(str + str_len - sfx_len, sfx) == 0;
133 }
134
135 /* Symbol versioning is different between static and shared library.
136 * Properly versioned symbols are needed for shared library, but
137 * only the symbol of the new version is needed for static library.
138 * Starting with GNU C 10, use symver attribute instead of .symver assembler
139 * directive, which works better with GCC LTO builds.
140 */
141 #if defined(SHARED) && defined(__GNUC__) && __GNUC__ >= 10
142
143 #define DEFAULT_VERSION(internal_name, api_name, version) \
144 __attribute__((symver(#api_name "@@" #version)))
145 #define COMPAT_VERSION(internal_name, api_name, version) \
146 __attribute__((symver(#api_name "@" #version)))
147
148 #elif defined(SHARED)
149
150 #define COMPAT_VERSION(internal_name, api_name, version) \
151 asm(".symver " #internal_name "," #api_name "@" #version);
152 #define DEFAULT_VERSION(internal_name, api_name, version) \
153 asm(".symver " #internal_name "," #api_name "@@" #version);
154
155 #else /* !SHARED */
156
157 #define COMPAT_VERSION(internal_name, api_name, version)
158 #define DEFAULT_VERSION(internal_name, api_name, version) \
159 extern typeof(internal_name) api_name \
160 __attribute__((alias(#internal_name)));
161
162 #endif
163
164 extern void libbpf_print(enum libbpf_print_level level,
165 const char *format, ...)
166 __attribute__((format(printf, 2, 3)));
167
168 #define __pr(level, fmt, ...) \
169 do { \
170 libbpf_print(level, "libbpf: " fmt, ##__VA_ARGS__); \
171 } while (0)
172
173 #define pr_warn(fmt, ...) __pr(LIBBPF_WARN, fmt, ##__VA_ARGS__)
174 #define pr_info(fmt, ...) __pr(LIBBPF_INFO, fmt, ##__VA_ARGS__)
175 #define pr_debug(fmt, ...) __pr(LIBBPF_DEBUG, fmt, ##__VA_ARGS__)
176
177 /**
178 * @brief **libbpf_errstr()** returns string corresponding to numeric errno
179 * @param err negative numeric errno
180 * @return pointer to string representation of the errno, that is invalidated
181 * upon the next call.
182 */
183 const char *libbpf_errstr(int err);
184
185 #define errstr(err) libbpf_errstr(err)
186
187 #ifndef __has_builtin
188 #define __has_builtin(x) 0
189 #endif
190
191 struct bpf_link {
192 int (*detach)(struct bpf_link *link);
193 void (*dealloc)(struct bpf_link *link);
194 char *pin_path; /* NULL, if not pinned */
195 int fd; /* hook FD, -1 if not applicable */
196 bool disconnected;
197 };
198
199 /*
200 * Re-implement glibc's reallocarray() for libbpf internal-only use.
201 * reallocarray(), unfortunately, is not available in all versions of glibc,
202 * so requires extra feature detection and using reallocarray() stub from
203 * <tools/libc_compat.h> and COMPAT_NEED_REALLOCARRAY. All this complicates
204 * build of libbpf unnecessarily and is just a maintenance burden. Instead,
205 * it's trivial to implement libbpf-specific internal version and use it
206 * throughout libbpf.
207 */
libbpf_reallocarray(void * ptr,size_t nmemb,size_t size)208 static inline void *libbpf_reallocarray(void *ptr, size_t nmemb, size_t size)
209 {
210 size_t total;
211
212 #if __has_builtin(__builtin_mul_overflow)
213 if (unlikely(__builtin_mul_overflow(nmemb, size, &total)))
214 return NULL;
215 #else
216 if (size == 0 || nmemb > ULONG_MAX / size)
217 return NULL;
218 total = nmemb * size;
219 #endif
220 return realloc(ptr, total);
221 }
222
223 /* Copy up to sz - 1 bytes from zero-terminated src string and ensure that dst
224 * is zero-terminated string no matter what (unless sz == 0, in which case
225 * it's a no-op). It's conceptually close to FreeBSD's strlcpy(), but differs
226 * in what is returned. Given this is internal helper, it's trivial to extend
227 * this, when necessary. Use this instead of strncpy inside libbpf source code.
228 */
libbpf_strlcpy(char * dst,const char * src,size_t sz)229 static inline void libbpf_strlcpy(char *dst, const char *src, size_t sz)
230 {
231 size_t i;
232
233 if (sz == 0)
234 return;
235
236 sz--;
237 for (i = 0; i < sz && src[i]; i++)
238 dst[i] = src[i];
239 dst[i] = '\0';
240 }
241
242 __u32 get_kernel_version(void);
243
244 struct btf;
245 struct btf_type;
246
247 struct btf_type *btf_type_by_id(const struct btf *btf, __u32 type_id);
248 const char *btf_kind_str(const struct btf_type *t);
249 const struct btf_type *skip_mods_and_typedefs(const struct btf *btf, __u32 id, __u32 *res_id);
250 const struct btf_header *btf_header(const struct btf *btf);
251 void btf_set_base_btf(struct btf *btf, const struct btf *base_btf);
252 int btf_relocate(struct btf *btf, const struct btf *base_btf, __u32 **id_map);
253
btf_func_linkage(const struct btf_type * t)254 static inline enum btf_func_linkage btf_func_linkage(const struct btf_type *t)
255 {
256 return (enum btf_func_linkage)(int)btf_vlen(t);
257 }
258
btf_type_info(int kind,int vlen,int kflag)259 static inline __u32 btf_type_info(int kind, int vlen, int kflag)
260 {
261 return (kflag << 31) | (kind << 24) | vlen;
262 }
263
264 enum map_def_parts {
265 MAP_DEF_MAP_TYPE = 0x001,
266 MAP_DEF_KEY_TYPE = 0x002,
267 MAP_DEF_KEY_SIZE = 0x004,
268 MAP_DEF_VALUE_TYPE = 0x008,
269 MAP_DEF_VALUE_SIZE = 0x010,
270 MAP_DEF_MAX_ENTRIES = 0x020,
271 MAP_DEF_MAP_FLAGS = 0x040,
272 MAP_DEF_NUMA_NODE = 0x080,
273 MAP_DEF_PINNING = 0x100,
274 MAP_DEF_INNER_MAP = 0x200,
275 MAP_DEF_MAP_EXTRA = 0x400,
276
277 MAP_DEF_ALL = 0x7ff, /* combination of all above */
278 };
279
280 struct btf_map_def {
281 enum map_def_parts parts;
282 __u32 map_type;
283 __u32 key_type_id;
284 __u32 key_size;
285 __u32 value_type_id;
286 __u32 value_size;
287 __u32 max_entries;
288 __u32 map_flags;
289 __u32 numa_node;
290 __u32 pinning;
291 __u64 map_extra;
292 };
293
294 int parse_btf_map_def(const char *map_name, struct btf *btf,
295 const struct btf_type *def_t, bool strict,
296 struct btf_map_def *map_def, struct btf_map_def *inner_def);
297
298 void *libbpf_add_mem(void **data, size_t *cap_cnt, size_t elem_sz,
299 size_t cur_cnt, size_t max_cnt, size_t add_cnt);
300 int libbpf_ensure_mem(void **data, size_t *cap_cnt, size_t elem_sz, size_t need_cnt);
301
libbpf_is_mem_zeroed(const char * p,ssize_t len)302 static inline bool libbpf_is_mem_zeroed(const char *p, ssize_t len)
303 {
304 while (len > 0) {
305 if (*p)
306 return false;
307 p++;
308 len--;
309 }
310 return true;
311 }
312
libbpf_validate_opts(const char * opts,size_t opts_sz,size_t user_sz,const char * type_name)313 static inline bool libbpf_validate_opts(const char *opts,
314 size_t opts_sz, size_t user_sz,
315 const char *type_name)
316 {
317 if (user_sz < sizeof(size_t)) {
318 pr_warn("%s size (%zu) is too small\n", type_name, user_sz);
319 return false;
320 }
321 if (!libbpf_is_mem_zeroed(opts + opts_sz, (ssize_t)user_sz - opts_sz)) {
322 pr_warn("%s has non-zero extra bytes\n", type_name);
323 return false;
324 }
325 return true;
326 }
327
328 #define OPTS_VALID(opts, type) \
329 (!(opts) || libbpf_validate_opts((const char *)opts, \
330 offsetofend(struct type, \
331 type##__last_field), \
332 (opts)->sz, #type))
333 #define OPTS_HAS(opts, field) \
334 ((opts) && opts->sz >= offsetofend(typeof(*(opts)), field))
335 #define OPTS_GET(opts, field, fallback_value) \
336 (OPTS_HAS(opts, field) ? (opts)->field : fallback_value)
337 #define OPTS_SET(opts, field, value) \
338 do { \
339 if (OPTS_HAS(opts, field)) \
340 (opts)->field = value; \
341 } while (0)
342
343 #define OPTS_ZEROED(opts, last_nonzero_field) \
344 ({ \
345 ssize_t __off = offsetofend(typeof(*(opts)), last_nonzero_field); \
346 !(opts) || libbpf_is_mem_zeroed((const void *)opts + __off, \
347 (opts)->sz - __off); \
348 })
349
350 enum kern_feature_id {
351 /* v4.14: kernel support for program & map names. */
352 FEAT_PROG_NAME,
353 /* v5.2: kernel support for global data sections. */
354 FEAT_GLOBAL_DATA,
355 /* BTF support */
356 FEAT_BTF,
357 /* BTF_KIND_FUNC and BTF_KIND_FUNC_PROTO support */
358 FEAT_BTF_FUNC,
359 /* BTF_KIND_VAR and BTF_KIND_DATASEC support */
360 FEAT_BTF_DATASEC,
361 /* BTF_FUNC_GLOBAL is supported */
362 FEAT_BTF_GLOBAL_FUNC,
363 /* BPF_F_MMAPABLE is supported for arrays */
364 FEAT_ARRAY_MMAP,
365 /* kernel support for expected_attach_type in BPF_PROG_LOAD */
366 FEAT_EXP_ATTACH_TYPE,
367 /* bpf_probe_read_{kernel,user}[_str] helpers */
368 FEAT_PROBE_READ_KERN,
369 /* BPF_PROG_BIND_MAP is supported */
370 FEAT_PROG_BIND_MAP,
371 /* Kernel support for module BTFs */
372 FEAT_MODULE_BTF,
373 /* BTF_KIND_FLOAT support */
374 FEAT_BTF_FLOAT,
375 /* BPF perf link support */
376 FEAT_PERF_LINK,
377 /* BTF_KIND_DECL_TAG support */
378 FEAT_BTF_DECL_TAG,
379 /* BTF_KIND_TYPE_TAG support */
380 FEAT_BTF_TYPE_TAG,
381 /* memcg-based accounting for BPF maps and progs */
382 FEAT_MEMCG_ACCOUNT,
383 /* BPF cookie (bpf_get_attach_cookie() BPF helper) support */
384 FEAT_BPF_COOKIE,
385 /* BTF_KIND_ENUM64 support and BTF_KIND_ENUM kflag support */
386 FEAT_BTF_ENUM64,
387 /* Kernel uses syscall wrapper (CONFIG_ARCH_HAS_SYSCALL_WRAPPER) */
388 FEAT_SYSCALL_WRAPPER,
389 /* BPF multi-uprobe link support */
390 FEAT_UPROBE_MULTI_LINK,
391 /* Kernel supports arg:ctx tag (__arg_ctx) for global subprogs natively */
392 FEAT_ARG_CTX_TAG,
393 /* Kernel supports '?' at the front of datasec names */
394 FEAT_BTF_QMARK_DATASEC,
395 /* Kernel supports LDIMM64 imm offsets past 512 MiB. */
396 FEAT_LDIMM64_FULL_RANGE_OFF,
397 __FEAT_CNT,
398 };
399
400 enum kern_feature_result {
401 FEAT_UNKNOWN = 0,
402 FEAT_SUPPORTED = 1,
403 FEAT_MISSING = 2,
404 };
405
406 struct kern_feature_cache {
407 enum kern_feature_result res[__FEAT_CNT];
408 int token_fd;
409 };
410
411 bool feat_supported(struct kern_feature_cache *cache, enum kern_feature_id feat_id);
412 bool kernel_supports(const struct bpf_object *obj, enum kern_feature_id feat_id);
413
414 int probe_kern_syscall_wrapper(int token_fd);
415 int probe_memcg_account(int token_fd);
416 int bump_rlimit_memlock(void);
417
418 int parse_cpu_mask_str(const char *s, bool **mask, int *mask_sz);
419 int parse_cpu_mask_file(const char *fcpu, bool **mask, int *mask_sz);
420 int libbpf__load_raw_btf(const char *raw_types, size_t types_len,
421 const char *str_sec, size_t str_len,
422 int token_fd);
423 int btf_load_into_kernel(struct btf *btf,
424 char *log_buf, size_t log_sz, __u32 log_level,
425 int token_fd);
426 struct btf *btf_load_from_kernel(__u32 id, struct btf *base_btf, int token_fd);
427
428 struct btf *btf_get_from_fd(int btf_fd, struct btf *base_btf);
429 void btf_get_kernel_prefix_kind(enum bpf_attach_type attach_type,
430 const char **prefix, int *kind);
431
432 struct btf_ext_info {
433 /*
434 * info points to the individual info section (e.g. func_info and
435 * line_info) from the .BTF.ext. It does not include the __u32 rec_size.
436 */
437 void *info;
438 __u32 rec_size;
439 __u32 len;
440 /* optional (maintained internally by libbpf) mapping between .BTF.ext
441 * section and corresponding ELF section. This is used to join
442 * information like CO-RE relocation records with corresponding BPF
443 * programs defined in ELF sections
444 */
445 __u32 *sec_idxs;
446 int sec_cnt;
447 };
448
449 #define for_each_btf_ext_sec(seg, sec) \
450 for (sec = (seg)->info; \
451 (void *)sec < (seg)->info + (seg)->len; \
452 sec = (void *)sec + sizeof(struct btf_ext_info_sec) + \
453 (seg)->rec_size * sec->num_info)
454
455 #define for_each_btf_ext_rec(seg, sec, i, rec) \
456 for (i = 0, rec = (void *)&(sec)->data; \
457 i < (sec)->num_info; \
458 i++, rec = (void *)rec + (seg)->rec_size)
459
460 /*
461 * The .BTF.ext ELF section layout defined as
462 * struct btf_ext_header
463 * func_info subsection
464 *
465 * The func_info subsection layout:
466 * record size for struct bpf_func_info in the func_info subsection
467 * struct btf_ext_info_sec for section #1
468 * a list of bpf_func_info records for section #1
469 * where struct bpf_func_info mimics one in include/uapi/linux/bpf.h
470 * but may not be identical
471 * struct btf_ext_info_sec for section #2
472 * a list of bpf_func_info records for section #2
473 * ......
474 *
475 * Note that the bpf_func_info record size in .BTF.ext may not
476 * be the same as the one defined in include/uapi/linux/bpf.h.
477 * The loader should ensure that record_size meets minimum
478 * requirement and pass the record as is to the kernel. The
479 * kernel will handle the func_info properly based on its contents.
480 */
481 struct btf_ext_header {
482 __u16 magic;
483 __u8 version;
484 __u8 flags;
485 __u32 hdr_len;
486
487 /* All offsets are in bytes relative to the end of this header */
488 __u32 func_info_off;
489 __u32 func_info_len;
490 __u32 line_info_off;
491 __u32 line_info_len;
492
493 /* optional part of .BTF.ext header */
494 __u32 core_relo_off;
495 __u32 core_relo_len;
496 };
497
498 struct btf_ext {
499 union {
500 struct btf_ext_header *hdr;
501 void *data;
502 };
503 void *data_swapped;
504 bool swapped_endian;
505 struct btf_ext_info func_info;
506 struct btf_ext_info line_info;
507 struct btf_ext_info core_relo_info;
508 __u32 data_size;
509 };
510
511 struct btf_ext_info_sec {
512 __u32 sec_name_off;
513 __u32 num_info;
514 /* Followed by num_info * record_size number of bytes */
515 __u8 data[];
516 };
517
518 /* The minimum bpf_func_info checked by the loader */
519 struct bpf_func_info_min {
520 __u32 insn_off;
521 __u32 type_id;
522 };
523
524 /* The minimum bpf_line_info checked by the loader */
525 struct bpf_line_info_min {
526 __u32 insn_off;
527 __u32 file_name_off;
528 __u32 line_off;
529 __u32 line_col;
530 };
531
532 /* Functions to byte-swap info records */
533
534 typedef void (*info_rec_bswap_fn)(void *);
535
bpf_func_info_bswap(struct bpf_func_info * i)536 static inline void bpf_func_info_bswap(struct bpf_func_info *i)
537 {
538 i->insn_off = bswap_32(i->insn_off);
539 i->type_id = bswap_32(i->type_id);
540 }
541
bpf_line_info_bswap(struct bpf_line_info * i)542 static inline void bpf_line_info_bswap(struct bpf_line_info *i)
543 {
544 i->insn_off = bswap_32(i->insn_off);
545 i->file_name_off = bswap_32(i->file_name_off);
546 i->line_off = bswap_32(i->line_off);
547 i->line_col = bswap_32(i->line_col);
548 }
549
bpf_core_relo_bswap(struct bpf_core_relo * i)550 static inline void bpf_core_relo_bswap(struct bpf_core_relo *i)
551 {
552 i->insn_off = bswap_32(i->insn_off);
553 i->type_id = bswap_32(i->type_id);
554 i->access_str_off = bswap_32(i->access_str_off);
555 i->kind = bswap_32(i->kind);
556 }
557
558 enum btf_field_iter_kind {
559 BTF_FIELD_ITER_IDS,
560 BTF_FIELD_ITER_STRS,
561 };
562
563 struct btf_field_desc {
564 /* once-per-type offsets */
565 int t_off_cnt, t_offs[2];
566 /* member struct size, or zero, if no members */
567 int m_sz;
568 /* repeated per-member offsets */
569 int m_off_cnt, m_offs[1];
570 };
571
572 struct btf_field_iter {
573 struct btf_field_desc desc;
574 void *p;
575 int m_idx;
576 int off_idx;
577 int vlen;
578 };
579
580 int btf_field_iter_init(struct btf_field_iter *it, struct btf_type *t, enum btf_field_iter_kind iter_kind);
581 __u32 *btf_field_iter_next(struct btf_field_iter *it);
582
583 typedef int (*type_id_visit_fn)(__u32 *type_id, void *ctx);
584 typedef int (*str_off_visit_fn)(__u32 *str_off, void *ctx);
585 int btf_ext_visit_type_ids(struct btf_ext *btf_ext, type_id_visit_fn visit, void *ctx);
586 int btf_ext_visit_str_offs(struct btf_ext *btf_ext, str_off_visit_fn visit, void *ctx);
587 __s32 btf__find_by_name_kind_own(const struct btf *btf, const char *type_name,
588 __u32 kind);
589
590 /* handle direct returned errors */
libbpf_err(int ret)591 static inline int libbpf_err(int ret)
592 {
593 if (ret < 0)
594 errno = -ret;
595 return ret;
596 }
597
598 /* handle errno-based (e.g., syscall or libc) errors according to libbpf's
599 * strict mode settings
600 */
libbpf_err_errno(int ret)601 static inline int libbpf_err_errno(int ret)
602 {
603 /* errno is already assumed to be set on error */
604 return ret < 0 ? -errno : ret;
605 }
606
607 /* handle error for pointer-returning APIs, err is assumed to be < 0 always */
libbpf_err_ptr(int err)608 static inline void *libbpf_err_ptr(int err)
609 {
610 /* set errno on error, this doesn't break anything */
611 errno = -err;
612 return NULL;
613 }
614
615 /* handle pointer-returning APIs' error handling */
libbpf_ptr(void * ret)616 static inline void *libbpf_ptr(void *ret)
617 {
618 /* set errno on error, this doesn't break anything */
619 if (IS_ERR(ret))
620 errno = -PTR_ERR(ret);
621
622 return IS_ERR(ret) ? NULL : ret;
623 }
624
str_is_empty(const char * s)625 static inline bool str_is_empty(const char *s)
626 {
627 return !s || !s[0];
628 }
629
is_ldimm64_insn(struct bpf_insn * insn)630 static inline bool is_ldimm64_insn(struct bpf_insn *insn)
631 {
632 return insn->code == (BPF_LD | BPF_IMM | BPF_DW);
633 }
634
bpf_insn_bswap(struct bpf_insn * insn)635 static inline void bpf_insn_bswap(struct bpf_insn *insn)
636 {
637 __u8 tmp_reg = insn->dst_reg;
638
639 insn->dst_reg = insn->src_reg;
640 insn->src_reg = tmp_reg;
641 insn->off = bswap_16(insn->off);
642 insn->imm = bswap_32(insn->imm);
643 }
644
645 /* Unconditionally dup FD, ensuring it doesn't use [0, 2] range.
646 * Original FD is not closed or altered in any other way.
647 * Preserves original FD value, if it's invalid (negative).
648 */
dup_good_fd(int fd)649 static inline int dup_good_fd(int fd)
650 {
651 if (fd < 0)
652 return fd;
653 return fcntl(fd, F_DUPFD_CLOEXEC, 3);
654 }
655
656 /* if fd is stdin, stdout, or stderr, dup to a fd greater than 2
657 * Takes ownership of the fd passed in, and closes it if calling
658 * fcntl(fd, F_DUPFD_CLOEXEC, 3).
659 */
ensure_good_fd(int fd)660 static inline int ensure_good_fd(int fd)
661 {
662 int old_fd = fd, saved_errno;
663
664 if (fd < 0)
665 return fd;
666 if (fd < 3) {
667 fd = dup_good_fd(fd);
668 saved_errno = errno;
669 close(old_fd);
670 errno = saved_errno;
671 if (fd < 0) {
672 pr_warn("failed to dup FD %d to FD > 2: %d\n", old_fd, -saved_errno);
673 errno = saved_errno;
674 }
675 }
676 return fd;
677 }
678
sys_dup3(int oldfd,int newfd,int flags)679 static inline int sys_dup3(int oldfd, int newfd, int flags)
680 {
681 return syscall(__NR_dup3, oldfd, newfd, flags);
682 }
683
684 /* Some versions of Android don't provide memfd_create() in their libc
685 * implementation, so avoid complications and just go straight to Linux
686 * syscall.
687 */
sys_memfd_create(const char * name,unsigned flags)688 static inline int sys_memfd_create(const char *name, unsigned flags)
689 {
690 return syscall(__NR_memfd_create, name, flags);
691 }
692
693 /* Point *fixed_fd* to the same file that *tmp_fd* points to.
694 * Regardless of success, *tmp_fd* is closed.
695 * Whatever *fixed_fd* pointed to is closed silently.
696 */
reuse_fd(int fixed_fd,int tmp_fd)697 static inline int reuse_fd(int fixed_fd, int tmp_fd)
698 {
699 int err;
700
701 err = sys_dup3(tmp_fd, fixed_fd, O_CLOEXEC);
702 err = err < 0 ? -errno : 0;
703 close(tmp_fd); /* clean up temporary FD */
704 return err;
705 }
706
707 /* The following two functions are exposed to bpftool */
708 int bpf_core_add_cands(struct bpf_core_cand *local_cand,
709 size_t local_essent_len,
710 const struct btf *targ_btf,
711 const char *targ_btf_name,
712 int targ_start_id,
713 struct bpf_core_cand_list *cands);
714 void bpf_core_free_cands(struct bpf_core_cand_list *cands);
715
716 struct usdt_manager *usdt_manager_new(struct bpf_object *obj);
717 void usdt_manager_free(struct usdt_manager *man);
718 struct bpf_link * usdt_manager_attach_usdt(struct usdt_manager *man,
719 const struct bpf_program *prog,
720 pid_t pid, const char *path,
721 const char *usdt_provider, const char *usdt_name,
722 __u64 usdt_cookie);
723
is_pow_of_2(size_t x)724 static inline bool is_pow_of_2(size_t x)
725 {
726 return x && (x & (x - 1)) == 0;
727 }
728
ror32(__u32 v,int bits)729 static inline __u32 ror32(__u32 v, int bits)
730 {
731 return (v >> bits) | (v << (32 - bits));
732 }
733
734 #define PROG_LOAD_ATTEMPTS 5
735 int sys_bpf_prog_load(union bpf_attr *attr, unsigned int size, int attempts);
736
737 bool glob_match(const char *str, const char *pat);
738
739 long elf_find_func_offset(Elf *elf, const char *binary_path, const char *name);
740 long elf_find_func_offset_from_file(const char *binary_path, const char *name);
741
742 struct elf_fd {
743 Elf *elf;
744 int fd;
745 };
746
747 int elf_open(const char *binary_path, struct elf_fd *elf_fd);
748 void elf_close(struct elf_fd *elf_fd);
749
750 int elf_resolve_syms_offsets(const char *binary_path, int cnt,
751 const char **syms, unsigned long **poffsets,
752 int st_type);
753 int elf_resolve_pattern_offsets(const char *binary_path, const char *pattern,
754 unsigned long **poffsets, size_t *pcnt);
755
756 int probe_fd(int fd);
757
758 #define SHA256_DIGEST_LENGTH 32
759 #define SHA256_DWORD_SIZE SHA256_DIGEST_LENGTH / sizeof(__u64)
760
761 void libbpf_sha256(const void *data, size_t len, __u8 out[SHA256_DIGEST_LENGTH]);
762 #endif /* __LIBBPF_LIBBPF_INTERNAL_H */
763